If the fakephp driver is used to emulate removal of a PCI device by
writing text string "0" to the "power" sysfs attribute file, this causes
its parent directory and its contents (including the "power" file) to be
deleted before the write operation returns. Unfortunately, it ends up
in a deadlock waiting for itself to complete.
The deadlock is as follows: sysfs_write_file calls flush_write_buffer
which calls sysfs_get_active_two before calling power_write_file in
pci_hotplug_core.c via the sysfs store operation. The power_write_file
function calls disable_slot in fakephp.c via the slot operation. The
disable_slot function calls remove_slot which calls pci_hp_deregister
(back in pci_hotplug_core.c) which calls fs_remove_slot which calls
sysfs_remove_file to remove the "power" file. The sysfs_remove_file
function calls sysfs_hash_and_remove which calls sysfs_addrm_finish
which calls sysfs_deactivate. The sysfs_deactivate function sees that
something has an active reference on the sysfs_dirent (from the
previous call to sysfs_get_active_two back up the call stack somewhere)
so waits for the active reference to go away, which is of course
impossible.
The problem has been present since 2.6.21.
This patch breaks the deadlock by queuing work queue items on a single-
threaded work queue to remove a slot from sysfs, and to rescan the PCI
buses. There is also some protection against disabling a slot that is
already being removed.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Cc: Kristen Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Disable Bus Master, SERR# and INTx to ensure that no new Requests will
be generated from the device before turning power off, in accordance
with the specification.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Set Bad DLLP Mask bit in Correctable Error Mask Register during
turning power off the slot.
This is the workaround against Bad DLLP error that sometimes happen
during turning power off on the slot which conforms to PCI Express
1.0a spec. The cause of this error seems that PCI Express 1.0a spec
doesn't have the following consideration that was added to PCI Express
1.1 spec.
"If the port is associated with a hot-pluggable slot (Hot-Plug
Capable bit in the Slot Capabilities register set to 1b), and
Power Controller Control bit in Slot Control register is 1b(Off),
then any transition to DL Inactive must not be considered an
error."
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
acpi_get_name() is called before and after dbg(). The latter is
useless and should be removed.
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Earlier patches to split out the hardware init for PCIe hotplug resulted in
some one-time initializations being redone on every resume cycle. Eg.
irq/polling initialization.
This patch splits the hardware init into two parts, and separates the
one-time initializations from those so that they only ever get done once,
as intended.
Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Make use of the previously split out pcie_init_enable_events() function
to reinitialize the hotplug hardware on resume from suspend, but only
when pciehp_force==1. Otherwise behaviour is unmodified.
Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Split out the hotplug hardware initialization code from pcie_init()
into pcie_init_enable_events(), without changing any functionality.
Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Fix presentation of the slot number in the /sys/bus/pci/slots
directory to match that used in the majority of other drivers.
> Greg said:
> How is anyone supposed to write sane managability tools in the
> presence
> of such anarchy?
>
> > ~ # cat /sys/bus/pci/slots/0000:00:02.2/phy_location
> > U787A.001.DNZ00Z5-P1-C2
>
> Right. This should look like:
>
> # cat /sys/bus/pci/slots/U787A.001.DNZ00Z5-P1-C2/address
> 0000:00:02
This patch implements exactly what you describe. Boot tested.
I assume you really mean it -- if so, then please review and
ack the patch !?
I have absolutely no clue if this breaks any existing IBM tools.
I'm pretty sure it doesn't ... but attention Mike Strosaker! does it?
Signed-off-by: Linas Vepstas <linas@austin.ibm.com>
Cc: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Cc: <strosake@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Currently, fakephp will claim all devices; we really only want it
to claim those not in slots.
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Matthew Wilcox <matthew@wil.cx>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Thank you so much for your check & advise.
This time, I've tried on ibmphp_core.c, is it OK?
Signed-off-by: Joonwoo Park <joonwpark81@gmail.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
There is no need for kobject_unregister() anymore, thanks to Kay's
kobject cleanup changes, so replace all instances of it with
kobject_put().
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This allows an easier way to get to the kset associated with a struct
bus_type (you have three to choose from...) This will make it easier to
move these fields to be dynamic in a future patch.
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Ian Abbott
Kenji Kaneshige
Joe Perches
Rolf Eike Beer
MUNEDA Takahiro
Mark Lord
Linas Vepstas
Alex Chiang
Kristen Carlson Accardi
Joonwoo Park
Paul Mackerras
Greg Kroah-Hartman